Metallic glasses fail by the formation of localized shear bands, which leads to catastrophic failure. Metallic glass specimens that are loaded in a state of plane stress fail on one dominant shear band and show little inelastic behavior. Metallic glass specimens loaded under constrained geometries (plane strain) fail in an elastic-perfectly-plastic manner by the generation of multiple shear bands. Multiple shear bands are observed when the catastrophic instability is avoided via mechanical constraint; e.g., in uniaxial compression, bending, drawing, and under localized indentation. There are a number of models that attempt to describe the formation of shear bands in metallic glasses, and at present these models do not fully describe the experimental observations.
A new class of ductile metal reinforced bulk metallic glass matrix composite materials has been prepared that demonstrate improved mechanical properties. This newly designed engineering material exhibits both improved toughness and a large plastic strain to failure. The new material was designed for use in structural applications (aerospace and automotive, for example), and is also a promising material for application as an armor.